From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754518Ab1AUQkc (ORCPT ); Fri, 21 Jan 2011 11:40:32 -0500 Received: from mtagate7.uk.ibm.com ([194.196.100.167]:51065 "EHLO mtagate7.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754451Ab1AUQka (ORCPT ); Fri, 21 Jan 2011 11:40:30 -0500 Date: Fri, 21 Jan 2011 16:40:19 +0000 From: "Dr. David Alan Gilbert" To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, acme@ghostprotocols.net, mingo@elte.hu Cc: dave.martin@linaro.org Subject: [PATCH] fix perf Annotation of Thumb code Message-ID: <20110121163922.GA31398@davesworkthinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, In ARM's Thumb mode the bottom bit of the symbol address is set to mark the function as Thumb; the instructions are in reality 2 or 4 byte on 2 byte alignments, and when the +1 address is used in annotate it causes objdump to disassemble invalid instructions. The patch removes that bottom bit during symbol loading. This patch is against current linus's git, (2b1caf.....). Many thinks to Dave Martin for comments on an initial version of the patch. Dave (For reference this corresponds to this bug https://bugs.launchpad.net/linux-linaro/+bug/677547 ) Signed-off-by: Dr. David Alan Gilbert --- diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 15ccfba..36e76c1 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1161,6 +1161,13 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name, section_name = elf_sec__name(&shdr, secstrs); + /* On ARM, symbols for thumb functions have 1 added to + * the symbol address as a flag - remove it */ + if ((ehdr.e_machine == EM_ARM) && + (map->type == MAP__FUNCTION) && + (sym.st_value & 1)) + sym.st_value-=1; + if (self->kernel != DSO_TYPE_USER || kmodule) { char dso_name[PATH_MAX];